I know most people like and have success with the 'understand its not real' approach, but I always have more personal success when I treat voices as if they are real people. I.e.: if a real person told more a very convincing but far fetched and potentially harmful story, I would be free to choose not to believe it, if a real person told me to harm myself or another, I would be free to choose not to, to say no.
This doesn't help at all with making them any less unpleasant, but makes me feel more powerful and in control, and helps me take control over my own responses and reactions.
I hope she will feel better soon. Thanks for posting.